My husband grew up in the 1930s and 1940s in rural England where the family phone was of an older vintage than the family phones where I grew up. The house was an old one, and it was also rather large. Probably its relative affluence and its isolation were why the previous owners had made the somewhat up-market decision to go 'on the phone'. This would have been sometime in the early 1930s or possibly even the 1920s.
Candlestick phones were in two parts with the mouthpiece at the top of the part reminiscent of a candle-like structure. The earpiece was held on a cradle when the phone is not in use and lifted to the ear when it is in use.
The base of the later candlestick phones held a dial as shown.
The earlier candlestick phones, however, such as the one in my husband's family had no dial, just a disk stating the number of the phone and other information on making the call. An example is shown in the photograph.
Where the phones had a dial, local calls could be dialled directly, but longer distance calls had to be made through the operator at the telephone exchange. To get hold of her, you dialled zero, always just called 'O';. In fact, "Dial O for operator" was a stock phrase.
My husband's parents candlestick phone did not have a dial. Lifting the earpiece from its cradle attracted the attention of the operator - at least that was the idea. If she didn't answer - which was not uncommon if she was on another line or chatting, the caller would jiggled the cradle up and down repeatedly.
Once the operator answered, the caller simply gave her the number required. Once she had got it, she would say something like: "It's ringing for you, caller" or "You're through". She could if she so wished amuse herself by staying on the line and listening to the conversation. Callers could do nothing about this, however much they objected to it.
Quite apart from the fact that telephoning through the operator could be slow and often laborious, the phones themselves were awkward to use. Two hands were needed: one to hold the earpiece to the ear and the other to hold the mouthpiece to the mouth. This meant that one part of the phone had to be put down in order to write down messages.
One way round the problem was to mount the phone on the wall, but it was not easy to position so that its height was right for everyone.
The newer phones of the 1940s were far more convenient in that both the mouthpiece and the earpiece were in the same unit and could be held in one hand, so freeing the other for dialling and taking down messages.